Larval Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) growth on Georges Bank: a model with temperature, prey size, and turbulence forcing

1999 ◽  
Vol 56 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Andrew W Leising ◽  
Peter JS Franks
Keyword(s):  
Prey Density ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Variable Temperature ◽  
Larval Growth ◽  
Temperature Cycle ◽  
Melanogrammus Aeglefinus ◽  
Georges Bank ◽  
Temperature Cycles ◽  
Haddock Melanogrammus Aeglefinus

Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) on Georges Bank are subjected to a high degree of variability in temperature, turbulence, and prey densities, depending on when they are spawned and where they are advected. We have developed an individual-based model that includes the effect of varying prey density, turbulence, and temperature. Temperature effects were included by using a Q10-type adjustment to the standard metabolic rate as well as a second temperature-dependent term added to the overall ingestion ability of our model fish, a function of the swimming speed, capture efficiency, and "liveliness" of a fish. Three cases were analyzed: (i) constant food and temperature conditions, (ii) variable temperature cycles, and (iii) variable temperature cycles plus turbulence. We found that prey density, turbulence, and temperature ranges typical of the peak spawning season are variable enough to be limiting to larval growth. The timing and location of spawning are crucial to the survival of the larvae. Increasing the average temperature cycle by 1°C, as might occur due to climatological change or interannual variability, increased growth for larvae that were not growing well previously. The increased temperature failed to increase larval growth in areas where larvae were already growing at rates close to their maximum.

Recent Growth, Biochemical Composition and Prey Field of Larval Haddock (Melanogrammus aeglefinus) and Atlantic Cod (Gadus morhua) on Georges Bank

1987 ◽  
Vol 44 (1) ◽  
pp. 14-25 ◽  
Author(s):  
L. J. Buckley ◽  
R. G. Lough
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Dry Weight ◽  
Melanogrammus Aeglefinus ◽  
Good Growth ◽  
Georges Bank ◽  
Larval Population ◽  
Prey Biomass ◽  
Recent Growth ◽  
Haddock Melanogrammus Aeglefinus

A transect across southern Georges Bank in May 1983 showed higher levels of available prey for haddock (Melanogrammus aeglefinus) and cod (Gadus morhua) larvae at two stratified sites than at a well-mixed site. At the stratified sites, prey biomass was high (30–300 μg dry wt∙L−1) near the surface above the thermocline; values were lower and more uniform with depth (10–30 μg dry wt∙L−1) at the well-mixed site. Larval population centers generally coincided with prey biomass vertically. Recent growth in dry weight of haddock larvae as estimated by RNA–DNA ratio analysis was higher at the stratified sites (8–13%∙d−1) than at the well-mixed site (7%∙d−1). Larvae appeared to be in excellent condition at the stratified sites, but up to 50% of haddock larvae from the well-mixed site had RNA–DNA ratios in the range observed for starved larvae in the laboratory. Cod collected at the same site were in better condition and growing faster than haddock. The data support the hypotheses that (1) stratified conditions in the spring favor good growth and survival of haddock larvae and (2) cod larvae are better adapted to grow and survive in well-mixed waters at lower levels of available food than haddock larvae.

scholarly journals Fecundity estimation of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) of Georges Bank: Application of the autodiametric method

2009 ◽  
Vol 99 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Alexandre Alonso-Fernández ◽  
Ann Carole Vallejo ◽  
Fran Saborido-Rey ◽  
Hilario Murua ◽  
Edward A. Trippel
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Melanogrammus Aeglefinus ◽  
Georges Bank ◽  
Haddock Melanogrammus Aeglefinus

Survival and Abundance of Young Atlantic Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) as Indicators of Year-class Strength

1989 ◽  
Vol 46 (S1) ◽  
pp. s171-s182 ◽  
Author(s):  
Steven E. Campana ◽  
Kenneth T. Frank ◽  
Peter C. F. Hurley ◽  
Peter A. Koeller ◽  
Fred H. Page ◽  
...  
Keyword(s):  
Nova Scotia ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Larval Mortality ◽  
Larval Growth ◽  
Melanogrammus Aeglefinus ◽  
Larval Abundance ◽  
Life History Stage ◽  
Spawning Site ◽  
Haddock Melanogrammus Aeglefinus

To identify the life history stage(s) most influential in determining yearclass strength, we constructed and analyzed survival curves of the 1983, 1984, and 1985 cohorts of cod and haddock off Southwest Nova Scotia relative to their physical and biological environment. Relative abundance of each Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) yearclass was not reflected by egg or larval abundance in any year examined. However, abundance of both pelagic and settled juveniles did appear to reflect yearclass strength. Egg and larval mortality could not be consistently linked with advection from the spawning site, and did not covary with subsequent recruitment. In both species, mortality between the larval and juvenile stage was inversely correlated with yearclass strength, but sources of the mortality could not be identified. Larval growth was inversely related to mortality of the early larval stage and independent of larval abundance. However, juvenile growth was proportional to mortality and inversely related to abundance. Despite early life coexistence and similarities in spawning time and location, the relative yearclass strengths of cod and haddock in Southwest Nova Scotia were different, suggesting that the timing of local physical and biological events may play an important role in the recruitment success of these stocks.

Recruitment to Northwest Atlantic Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) Stocks: Influence of Stock Size and Climate

1987 ◽  
Vol 44 (1) ◽  
pp. 26-39 ◽  
Author(s):  
J. Anthony Koslow ◽  
Keith R. Thompson ◽  
William Silvert
Keyword(s):  
Large Scale ◽  
Gadus Morhua ◽  
Reproductive Output ◽  
Atlantic Cod ◽  
Low Frequency ◽  
Melanogrammus Aeglefinus ◽  
Northwest Atlantic ◽  
Biological Variables ◽  
Low Frequency Variability ◽  
Haddock Melanogrammus Aeglefinus

Year-class success of both Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) stocks in the northwest Atlantic exhibits large-scale coherence and low-frequency variability with apparent periodicities of 10–20 yr. Several physical and biological variables in the region exhibit similar large-scale coherence and apparent periodicity. Multiple regression analysis indicates that year-class success in northwest Atlantic cod stocks tends to be associated with large-scale meteorological patterns and offshore winds. Recruitment to most haddock stocks from the Scotian Shelf to Georges Bank is negatively associated with abundance of 0-group mackerel, which may be due to predation over winter and/or to a combination of environmental features including sea-surface temperature, large-scale atmospheric pressure systems, and freshwater outflows. Statistical analyses often did not define a unique set of variables that best predicted fishery recruitment due to widespread intercorrelations among environmental processes and the likelihood that not all relevant processes entered directly into the analyses. There is little evidence that stock reproductive output during the study period was significantly related to year-class success.

Development of the digestive capacity in larvae of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua)

Aquaculture ◽  
2006 ◽  
Vol 251 (2-4) ◽  
pp. 377-401 ◽  
Author(s):  
J.C. Perez-Casanova ◽  
H.M. Murray ◽  
J.W. Gallant ◽  
N.W. Ross ◽  
S.E. Douglas, ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Melanogrammus Aeglefinus ◽  
Digestive Capacity ◽  
Haddock Melanogrammus Aeglefinus

Does the fall phytoplankton bloom control recruitment of Georges Bank haddock, Melanogrammus aeglefinus, through parental condition?

2008 ◽  
Vol 65 (6) ◽  
pp. 1076-1086 ◽  
Author(s):  
Kevin D. Friedland ◽  
Jonathan A. Hare ◽  
Grayson B. Wood ◽  
Laurel A. Col ◽  
Lawrence J. Buckley ◽  
...  
Keyword(s):  
Phytoplankton Bloom ◽  
Larval Growth ◽  
Melanogrammus Aeglefinus ◽  
Georges Bank ◽  
Growth And Survival ◽  
Probability Of Survival ◽  
Bank Stock ◽  
Parental Condition ◽  
Recruitment Event ◽  
Haddock Melanogrammus Aeglefinus

In 2003, the Georges Bank stock of haddock ( Melanogrammus aeglefinus ) experienced the largest recruitment event recorded during its assessed history. Several hypotheses have been advanced to explain recruitment variability in this much-scrutinized stock, including variability in the retention of eggs and larvae on Georges Bank, the timing of haddock spawning, and variability in the spring bloom, which influences larval growth and survival. Although these processes may contribute to the formation of successful year classes, none of the factors associated with these previous hypotheses provides an adequate explanation of the 2003 recruitment event. We analyzed data on the dynamics of the fall phytoplankton bloom the year prior to spawning and show it to be highly correlated with subsequent recruitment. We suggest that the fall bloom affects recruitment through enhanced condition of adults and by increasing the quantity and quality of their reproductive output, which in turn leads to a higher probability of survival of their offspring. Although synoptic data on the fall bloom are limited and our analyses are correlative, our purpose is to stimulate a rigorous test of this promising “parental condition hypothesis”.

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